What is a significant danger of volcanic ash to aircraft?

Volcanic ash poses a significant danger to aircraft primarily because it can lead to engine flameouts. When aircraft fly through volcanic ash clouds, the fine particles can enter the engines and cause thermal issues. The hot air inside the engine can cause the ash to melt and create a glass-like substance, which can obstruct airflow and damage essential components. This can ultimately result in a loss of thrust or complete engine failure, known as a flameout.

This danger is particularly critical at high altitudes where ash clouds tend to be concentrated, leading to situations that can endanger the safety of the flight. Other dangers associated with volcanic ash include potential damage to the airframe and windscreen, but the most severe risk remains the impact on engine performance, reinforcing why an engine flameout is a significant concern in aviation safety.